The increased playing of tennis, squash and racquet-ball by men and women over 30 years of age has led to the increase of a painful problem known as "tennis elbow". This condition usually occurs in people between 30 and 50 years of age, where muscles and tendons have become less supple and less able to absorb and dissipate vibrational shock.
Epicondylalgia externa (tennis elbow) is not only found in racquet sports but can be aggravated by other pursuits, such as, golf and bowling. It can also be found in certain trades, such as carpentry, due to repeated hammering and driving of screws, and in house painting, due to the forward and backward stroke of the brush. Also, it can be found in industrial jobs involving pneumatic hammers and the like.
The motive power that enables the forearm to be rotated from side to side comes from the wrist and not the elbow. Therefore, the start of the problem is at the wrist during pronation and supination. Shock and/or vibration occurring at the wrist is propagated up the extensor muscles until it terminates in the outer and supporting parts of the attachment to the head of the humerus called the lateral epicondyle and also the extensor tendon that attaches the forearm extensor muscles to the epicondyle. The vibration can also be propagated up the flexor muscles in the same manner.
The forearm extensor muscles are those that come into play during the extension, raising or snapping of the wrist. Every time a tennis ball hits a racquet there is a certain force propagated up the forearm muscles which are already in tension due to the weight and acceleration of the racquet and the tension caused by the centrifugal force of the stroke. If the ball is mis-hit, an extra force is added which leads to an upward snap of the wrist. It is this extra stress that travels up the extensor muscles to the epicondyle and causes the trauma leading to inflammation. To some extent, aluminum metal or graphite racquets tend to reduce the stress because of their light weight and also racquets with oversized heads tend to reduce the problem because the larger area that the ball can hit, without twisting the racquet, reduces the number of mis-hits.
Prior art procedures to control epicondylalgia externa include tension bandages for support and non-elastic bandages which are fastened around the forearm to inhibit the massive movement of the extensor and flexor muscles and so absorb much of the shock. Further, both wrist and forearm straps which are joined by a piece of spring metal and situated either on the top or bottom of the forearm have been used. This spring metal absorbs some of the massive shock occurring in the muscles but does not absorb the surface vibrations that do much of the damage and inhibit healing of the elbow.
In the parent application, the following U.S. patents have been cited as prior art and are made of record herein: U.S. Pat. Nos. 3,631,854, 3,561,435, 2,245,909, 2,943,859, 3,831,467, 3,900,035, 3,678,936, 2,749,914, 3,506,013, 4,116,236, 3,703,171, 4,204,543, 3,736,769, 4,044,773 and 3,149,943. These references relate generally to a variety of structures which are applied to various body parts and, as will become apparent from the discussions below, are not relevant to the present invention.
The use of heat as therapy for muscles or a group of muscles in the human body is a well-known technique. Prior art thermal pads employ some form of positive or external heating means, for example, electricity, chemical means, or steam or hot water. Typical prior art in this area are the following U.S. Pat. Nos.: 2,911,974, 2,909,176, 2,595,328, 3,463,161 and 3,901,225. As will become apparent from the discussion below, this prior art is not relevant to the present invention.